Swingarm swap and cleanup:

[mrbill5491]

Aaah one thing I forgot to mention, since the 1100 swing arm uses larger bearings, the front part of the swing arm is going to sit a lot closer to the back of your motor. When I saw it, I just said to myself, wow that is close lol. I had to route my drain hose from the air box around the swing arm rather then in between the swing arm and engine case. The 80-81 GS750E and 1100E have the same wheel base, and yes it is a bit longer then the 77 models.

[MK3Brent]

Aaah one thing I forgot to mention, since the 1100 swing arm uses larger bearings, the front part of the swing arm is going to sit a lot closer to the back of your motor. When I saw it, I just said to myself, wow that is close lol. I had to route my drain hose from the air box around the swing arm rather then in between the swing arm and engine case. The 80-81 GS750E and 1100E have the same wheel base, and yes it is a bit longer then the 77 models.

It is close, 1/32" clearance.

Good thing that part doesn't shift.

[mrbill5491]

It is close, 1/32" clearance.

Good thing that part doesn't shift.

For sure...

[allojohn]

See my attached thumbnail pic, My 77 GS750 measures 18-1/2" from center of the pivot to the very front of the axle slot, and the GS1100 swinger I have to install on it is DEFINITELY much longer, see pic.

Yep, so you'll need a longer chain. I did the '82 1100E swing arm and 530 conversion - forgot to take that onto account. Doh!

[MK3Brent]

Must be a difference in the years.

My bike is an 82'.

Was kind of a surprise it was a direct swap, minus the pivot bolt.

I had new chain/sprockets ready to go.

[Smurf]

Doing the Same Swap

I'm doing the same swap: GS1100E swingarm onto an 81 GS750E. SO...

How exactly do I do it? I don't want to drill out the frame. Do I need an 1100 pivot bolt or just the bushings?

[Smurf]

Also, I'm going to ditch the footpeg mounts and go with rearsets.

Also,also, HOW DID YOU GET THAT SWINGARM SO SHINEY???

[mrbill5491]

I'm doing the same swap: GS1100E swingarm onto an 81 GS750E. SO...

How exactly do I do it? I don't want to drill out the frame. Do I need an 1100 pivot bolt or just the bushings?

If you dont ream out the frame bushings ( note I didn't say drill, DO NOT DO THAT), you will have to have the swingarm inner races machined to take the stock 750 pivot bolt. Me I cut out the frame bushings and had some new ones made, welded them back in and a new 1100 pivot made since I kept my stock footpeg mounts. The 1100 bolt is about an inch and 3/4s too short that way.

[salty_monk]

Top hat style adapter bushes....

[Chuck78]

http://www.ebay.com/itm/110923368371

Is this the type of reamer that is recommended to enlarge the frame pivot holes? There are several styles, straight shank, tapered like this, some with a 45 degree angled tip and then straight shank... Even with one of these, I would be afraid of misalignment without having the frame jigged up in a drill press.

[Chuck78]

I was thinking of having my buddy with a machine shop at his disposal make a sleeve that would be the OD of the 1100 pivot bolt but have an ID that fit the 750 pivot bolt snugly. Not sure how difficult that would be for him to make. I need to hit him up for some aluminum 5mm thick rotor spacers anyway for my brake swap...

Does anyone know what the diameter of the 750 pivot bolt is, particularly the early GS750's, so I don't have to take mine out to measure! I have the 1100 parts sitting on the shelf to measure.

[mrbill5491]

http://www.ebay.com/itm/110923368371

Is this the type of reamer that is recommended to enlarge the frame pivot holes? There are several styles, straight shank, tapered like this, some with a 45 degree angled tip and then straight shank... Even with one of these, I would be afraid of misalignment without having the frame jigged up in a drill press.

When we looked at my frame to fix the frame swing arm bushings, we found or rather the machinist found it was about impossible to jig up the frame in his drill press, all the angles were just not going to work. It would cost too much for him or me just to build a special jig for one job. The best option was just cut out the old bushings, he make me an exact copy of the stock ones though 16 mm size for the 1100 swing arm pivot bolt and once welded back in they looked as close to stock as one can get. Everything fit just like stock too.

[Chuck78]

After reading this and other threads, apparently making a sleeve is something that needs to be done out of hardened steel, as the bearings will chew up any soft steel sleeve.

One of the posts I read last night had a machine shop use a long hardened steel sleeve of the correct OD, but too large of an ID, and had bronze bushing inserts machined down to fit the OD of the smaller bolt (on the inside of the bushing) and the ID of the sleeve (on the outside of the bushing) I believe.

I am a pretty stubborn and fairly resourceful guy, so I think I may just lay my bike over on it's side with the swinger removed, and set up some sort of jig to hold my drill press steady. I will verify it's squareness and centered position by first chucking up the largest bit out of my machinist's drill bit set that I can fit in the hole, and verifying alignment that way. Then I will probably purchase a 5/8" or similar reamer like in the picture above.

[Chuck78]

The width of the GS1100E swing arm with the used thrust washers, inner sleeve, hardened steel inner needle bearing race sleeve/spacer, thrust washers, and metal dust caps comes out to right around to 225mm width. I measured my 77 GS750 swing arm pivot bolt threads as installed on bike, and it appears that the bolt is a 14mm from that rough measurement (what I remembered reading), and I measured the shoulder on my GS1100E swing arm pivot bolt, and it measures dead on exactly 16mm.

What I had read about the machinist saying that the bearings would chew up the proposed sleeve to use the GS750 bolt seems to be bunk to me. The swingers ride on a set of needle bearings on each side, and the inner race is nothing more than a hardened steel flat cylindrical sleeve, and it is clamped in by the bolt tight between the frame and the center spacer, with the thrust washers and dust caps sandwiched in there as well.

Given all of that, I am not sure what effect it would have to put a fixed width 225mm sleeve in the middle of this, as 225mm would keep the thrust washers and dust caps located on the sleeve, but would not allow them to tighten down as intended to clamp in place the races and inner sleeve so they are fixed to the frame, allowing only the bearings to do the pivoting. cleaning the insides and applying permanent loctite as well...

I just had a momentary brainstorm of taking a 16mm drill bit to the insides of the frame to recess just a slight opening in there to allow for up to 1mm or so of compression and still allow use of the 225mm wide sleeve to make sure the dust caps and thrust washers stay located on the 16mm portion. EDIT - actually, making it about 224.8mm (or something like that but more scientifically determined) and slightly beveling the outer edges the thickness of the thin dust caps very slightly seems a far better idea, as to keep it fixed, yet still allow for proper compression of the frame if there is any flex in it.

[Chuck78]

I think I'm going to have my machinist friend make up some steel bushing sleeves to use the GS 750 bolt in the 1100 swing arm. Is there anyone else here that wants to go in on some while he is making them? I could use some input on the exact width to make the bushings not rattle around inside of the swing arm, yet still allow the frame to squeeze the thrust washers/ dust caps/ inner races/inner spacer to keep them fixed. I'm thinking 224.9mm or so, maybe 224.8mm. I think the inside frame width is a hair over 225mm.

I am also thinking that making them out of aluminum may be beneficial as well as much easier for the machinist. With aluminum, we could make the sleeve 225mm, and tightening the bolt down may crush into the soft metal while compressing the frame enough to keep the inner races and sleeve fixed as they have to be. Steel would maybe make it a negligible amount more rigid, although slightly heavier